1165 - Multimodal Pre-Guided Observation of Rectal Gas and OAR Dose Differences in Intracavitary Brachytherapy for Cervical Cancer: A Prospective Randomized Controlled Study
Presenter(s)
J. Ma1, F. Bai2, L. L. Xu3, H. Yang4, Y. Zhang5, L. C. Wei5, and L. Zhao6; 1Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University., Xi’an, shaanxi, China, 2Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, xi'an, Shaanxi, China, 3Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, xi'an, shaanxi, China, 4Department of radiation oncology, Xijing Hospital, the Fourth Military Medical University, Xi'an, China, 5Department of Radiation Oncology, First Affiliated Hospital of Air Force Medical University, Xi'an, China, 6StateKey Laboratory of Holisticntegrative Managementof Gastrointestinal Cancersand Department of RadiationOncology,Xijing Hospital,Fourth Military MedicalUniversity, Xi'an, China
Purpose/Objective(s):
Previous studies have reported accurate evaluation of rectal gas impact programs during intracavitary brachytherapy for cervical cancer. This study intends to conduct adequate bowel preparation by pre-guiding patients through multiple modes, and observe changes in rectal gas and volume of patients, as well as the impact on OAR dose.Materials/Methods:
This study included patients who received brachytherapy continuously in our center from March 2021 to March 2024. All patients were scheduled to receive brachytherapy 32Gy/4 F after completing a total pelvic irradiation dose of 50GY (IMRT technique). Patients with visible rectal gas above 5 cc on CT localization images of the first brachytherapy were randomly divided into intervention group and control group (numerical table method). After the first brachytherapy, professionals in both groups explained the same precautions for intestinal preparation in detail, including diet adjustment, abdominal massage, intestinal emptying before treatment, etc. The intervention group was then reminded daily via WeChat group, telephone or face-to-face communication, and reconfirmed the day before the next treatment to ensure adequate bowel preparation. Rectal gas volume, OAR and HR-CTV dose, toxicity and OS were observed.Results:
A total of 52 patients were included in the analysis, 26 in the intervention group and 26 in the control group. The median follow-up time was 24.5 months, and there was no statistical difference in baseline information between the two groups; the rectal gas volume at the first treatment was 22.81±12.69cc in the intervention group and 24.54±13.19cc in the control group, P=0.63. Rectal gas volume of the two groups at the second treatment was 1.47±2.06cc in the intervention group and 5.44±4.17cc in the control group, P<0.001; rectal volume after intervention was 35.02±9.86cc in the intervention group and 50.91±11.05cc in the control group, P<0.001. OAR dose analysis showed that there was no statistical significance in bladder, small intestine and sigmoid colon D2cc between the two groups, rectal D2cc was 69.61±2.54Gy in intervention group and 71.41±1.86Gy in control group, P=0.005; HR-CTVD90 was 85.46±1.98Gy in intervention group and 83.89±2.66Gy in control group, P=0.019. The incidence of radiation proctitis was 11.5%(3/26) in the test group and 34.6%(9/26) in the control group, X2 =3.9, p=0.048. There was no difference in OS between the two groups.Conclusion: This prospective study showed that rectal gas significantly affected OAR and dose to target during intracavitary brachytherapy for cervical cancer. Multi-mode pre-guidance can effectively reduce rectal gas production and volume, improve brachytherapy effect, and reduce the incidence of radiation proctitis. It is worthy of clinical application.